Mattress Protector Size Chart & Guide

Updated Nov 21, 2025

Your mattress is an investment in good sleep—and the right mattress protector helps keep it that way. From guarding against spills to adding a breathable layer of comfort, a properly fitted protector can make all the difference. Whether you’re upgrading your bed, switching mattress size, or just aiming to extend the life of your current setup, this guide will help you find the perfect fit in both coverage and quality.

What is a Mattress Protector?

First, what is a mattress protector, exactly? A mattress protector is a removable fabric cover that fits over your mattress like a fitted sheet to help guard against spills, stains, and everyday wear. It adds a layer of protection without changing the comfort or feel of your bed. Available in every mattress size, a good protector keeps your mattress clean, extends its lifespan, and helps you maintain a fresher, healthier sleep surface.

Mattress Protector Pocket Depth

Pocket depth refers to how many inches of your mattress a mattress protector can cover from top to bottom. It’s the measurement that determines how well the protector fits your bed and whether it stays snug or slips off during the night. Ideally, your protective mattress cover should be at least one inch deeper than your actual mattress to ensure a snug, comfortable fit that won’t shift as you sleep.

Mattress Protector Size Chart

As the sheath that covers your mattress, picking a mattress protector that has a secure fit and doesn’t pinch or sag is crucial to keeping your bed cozy and protected, making it a place you look forward to landing at the end of each day.

Read further for our mattress protector size guide.

Twin Mattress Protector Size

A twin bed has one of the smallest types of mattresses you’ll come across. Here are their stats:

• Measurements – 39″ x 75″
• Appropriate for – Kids, young adults, and adults sleeping solo

A twin mattress needs a twin-sized mattress protector. If you’re in search of young children’s bedding, remember to aim for high-quality waterproof backing like Casper’s Waterproof Mattress Protectors to protect against any accidents that occur in the wee hours (hey, it happens).

Twin XL Mattress Protector Size

Twin XL mattresses are slightly longer than Twin mattresses, with the same standard width. Here’s what to expect:

• Measurements – 39″ x 80″
• Appropriate for – Taller young adults and single adults.

It’s not uncommon to mistake a Twin XL-sized mattress protector for a standard Twin size when shopping. To ensure you get a secure fit, always measure your mattress’ dimensions to confirm they match up with those of the mattress protector before completing a purchase.

Full Mattress Protector Size

Sleep shoppers, take note: full mattresses and double mattresses are interchangeable in the world of bedding. Thus, when you dive into full vs. double beds, you’ll find they have the same dimensions:

• Measurements – 54″ x 75″
• Appropriate for – Young adults and single adults who crave more surface area to get their dreamiest-quality sleep.

Provided they share the above dimensions, a mattress protector described as “Full” should work for a Double mattress, and vice versa.

Queen Mattress Protector Size

Queen mattresses are perfect for sleepers who are ready to graduate to next-level quality sleep. Their stats are:

• Measurements – 60″ x 80″
• Appropriate for – Single adults and coupled-up sleepers.

In this scenario, you’ll need a Queen-sized mattress protector.

King Mattress Protector Size

King-sized mattresses are the broadest of the bunch, with the same length as Queen mattresses. Here’s how they measure up:

• Measurements – 76″ x 80″
• Appropriate for – Single adults and coupled-up sleepers who like plenty of wiggle room to sleep.

King mattresses pair with King-sized mattress protectors. When perusing the best mattress protection, make sure you don’t purchase a California King mattress protector, which is narrower and longer than standard King-sized mattresses.

Couples who share a King sized mattress should aim for styles that emphasize thermoregulation and airflow, like Casper’s Breathable Cooling Mattress Protector, to keep all bedmates comfortable during resting hours.

Cal King Mattress Protector Size

California King mattresses have a reputation for being the most spacious size in the mattress kingdom, but they actually have a smaller area than King mattresses. Here’s how they compare:

• Measurements – 72″ x 84″
• Appropriate for – Tall adults, couples, or anyone who wants plenty of legroom.

California King mattresses require a California King mattress protector. Because California King mattresses tend to come at a higher price point, it’s essential to choose the best waterproof mattress protector to guard your mattress against liquid damage and get the most out of your sleep.

What Size Mattress Protector Do I Need?

There’s one last dimension you’ll need to account for when picking the right mattress protector fit for your mattress: depth.

Cheaply made mattress protectors tend to use low-grade waterproof backing to protect your bed, which don’t have the same elasticity as more sophisticated designs. Depending on how thick your mattress depth is, a mattress protector that matches the width and length of your mattress may not be built to cover your model from top to bottom.

Moreover, a poor-quality mattress topper can lead to the following sleep downfalls:

• Discomfort – A poorly made mattress cover isn’t enjoyable to sleep on. Depending on the quality, you may even be able to feel it beneath your bedding—the pea to your prince or princess, but with a lot more surface area.
• Noise – Poor designs are known to make rustling sounds at the slightest shift of body weight. If you’re easily disturbed by noise at rest, seek out a higher-quality mattress protector that can keep the peace.
• Impracticality – Put simply, badly-designed mattress protectors won’t perform their main job: being a waterproof protector to keep liquids and other substances from staining your mattress.

Once you’ve picked the right size, make sure you pick the king of quality. Picking the right mattress protector will guard your mattress, add another layer of comfort, and help you ease into bed each night knowing you have years more dozing to do there.

Find Plush, Protected Mattresses with Casper

At Casper, we understand that building better sleep solutions means building better sleep quality and improving your physical and mental health.1

Investing in your sleep quality starts with the proper—and properly-sized—mattress protector. For your solution, check out our Casper mattress protector collection in every mattress size.

FAQs About Mattress Protector Sizes

Do you need a mattress protector?

Although you can still get a good night’s sleep without one, a mattress protector helps safeguard your bed from spills, stains, and allergens, extending the life of your mattress. It’s a simple way to maintain quality sleep and keep your mattress fresh for years to come.

Do mattress protectors make the bed less comfortable?

Not at all. A good mattress cover should feel soft, smooth, and barely noticeable under your sheets. Look for protectors made with breathable materials that preserve comfort while protecting your mattress from daily wear and tear.

What’s the difference between a mattress protector and a mattress pad?

A mattress protector is designed for protection—guarding against moisture and stains—while a mattress pad adds extra cushioning for comfort. Some sleepers use both for a bed that’s equally protected and plush.

Do mattress protectors make you sleep hot? 

If you’re used to sleeping hot, rest assured—quality mattress protectors, especially those made with breathable or cooling fabrics, won’t trap heat. They’re designed to promote airflow and maintain an even temperature, so you can stay cool and comfortable throughout the night.

Sources:

1. Healthline. 10 Reasons to Get More Sleep. https://www.healthline.com/nutrition/10-reasons-why-good-sleep-is-important#2.-Can-improve-concentration-and-productivity
2. The Sleep Foundation. What Factors Affect Sleep Quality? https://www.sleepfoundation.org/sleep-hygiene/how-is-sleep-quality-calculated